Remove the scriptz submodule and hard-commit the files.

The submodule is a leftover from when this project was intended to work
as a series of microservices. It was meant to provide common
functionality to the builds for every microservice. That's no longer the
case, and the submodule is a pain-point both in on-boarding new
developers and running the Docker build.

script/include/bootstrap_functions.inc.sh

@@ -0,0 +1,13 @@
+# bootstrap_functions.inc.sh: Functions used by the bootstrap script
+
+install_python_packages() {
+  local install_flags="${1}"
+
+  pipenv install ${install_flags}
+  return $?
+}
+
+install_node_packages() {
+  yarn install
+  return $?
+}